Semiconductor thermal field structural member and preparation method thereof

Abstract

The invention discloses a semiconductor thermal field structural member and a preparation method thereof. The preparation method comprises the following steps: a base material preparation step: preparing a carbonaceous base material, and placing the carbonaceous base material in a reaction container; preparing a silicon carbide layer, namely forming the silicon carbide layer on the surface of the carbonaceous base material through chemical vapor deposition; and preparing a tantalum carbide layer, namely forming the tantalum carbide layer on the surface of the silicon carbide layer through chemical vapor deposition. According to the preparation method disclosed by the invention, the silicon carbide layer is introduced between the carbonaceous base material and the tantalum carbide coating, and the thermal matching difference between the tantalum carbide coating and the carbonaceous base material is reduced by utilizing the characteristic that the thermal expansion coefficient of silicon carbide is between that of the carbonaceous base material and that of tantalum carbide, so that the high temperature resistance and corrosion resistance of the coating are ensured, and the coating is not easy to fall off.

Description

Technical Field

[0001] The present application generally relates to the field of semiconductor technology, and more specifically to a semiconductor thermal field structure and a method for preparing the same. Background Art

[0002] Semiconductor thermal field structures are mainly used in the preparation and processing of semiconductor materials, especially those involving crystal growth technology under high temperature conditions, such as the Czochralski method for preparing single crystal silicon. The design of the thermal field structure is crucial to the quality of semiconductor materials, which directly affects the crystal integrity, doping uniformity and final performance of semiconductor devices.

[0003] Graphite is easy to process, has high thermal stability, and has a melting point of 3850°C in an oxygen-free environment. Isostatic graphite has the characteristics of high strength, high density, uniformity, and isotropy. When heated, graphite exhibits a low thermal expansion coefficient and high thermal conductivity, which can effectively reduce the internal stress of the material caused by rapid cooling and heating, and form a uniform thermal field. Therefore, it is widely used in semiconductor thermal field structural parts. However, at high temperatures, graphite is easily oxidized by oxygen. 2 , H 2 , HCl, NH 3 The corrosion and powdering will lead to the decrease of the structural strength of the main body and affect the quality of the wafers in contact with it.

[0004] Therefore, a semiconductor thermal field structure and a preparation method thereof are needed to solve at least one technical problem. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] The present application is proposed to solve at least one of the above problems. Specifically, the first aspect of the present application provides a method for preparing a semiconductor thermal field structure, the method comprising the following steps:

[0007] providing a carbonaceous substrate;

[0008] forming a silicon carbide layer on the surface of the carbonaceous substrate by chemical vapor deposition;

[0009] A tantalum carbide layer is formed on a surface of the silicon carbide layer away from the carbonaceous substrate by chemical vapor deposition.

[0010] According to the preparation method of the present application, by introducing a silicon carbide layer between the carbonaceous substrate and the tantalum carbide coating, the thermal expansion coefficient of silicon carbide is between that of the carbonaceous substrate and tantalum carbide, so as to reduce the thermal matching difference between the tantalum carbide coating and the carbonaceous substrate, thereby ensuring that the coating is resistant to high temperature and corrosion and is not easy to fall off.

[0011] Optionally, the silicon carbide layer includes a silicon carbide inner layer and a silicon carbide transition layer, and the step of preparing the silicon carbide layer further includes:

[0012] A raw material gas introduction step, wherein a carbon source, a silicon source, hydrogen and an inert gas are introduced into the reaction container;

[0013] a step of preparing a silicon carbide inner layer, depositing the silicon carbide inner layer on the surface of the carbonaceous substrate;

[0014] The step of preparing the silicon carbide transition layer comprises changing the ratio of the carbon source and the silicon source, and depositing the silicon carbide transition layer on the surface of the silicon carbide inner layer.

[0015] Optionally, the step of preparing the tantalum carbide layer further includes: closing the silicon source, introducing a tantalum source into the reaction container, and depositing the tantalum carbide layer on the surface of the silicon carbide transition layer.

[0016] Optionally, the preparation method further comprises:

[0017] A post-processing step is performed after the step of preparing the tantalum carbide layer, and the post-processing step includes: shutting off the carbon source, the tantalum source and the hydrogen, and continuing to introduce the inert gas into the reaction container for gradient cooling.

[0018] Optionally, the preparation method further comprises a substrate pretreatment step, which is performed before the step of preparing the silicon carbide layer, and the substrate pretreatment step comprises: activating the surface of the carbonaceous substrate.

[0019] Optionally, the activation treatment includes at least one of ultrasonic treatment, heat treatment, plasma treatment, acid treatment, alkali treatment and high-temperature purification.

[0020] Optionally, the activation treatment includes: introducing hydrogen into the reaction container, performing temperature activation, controlling the hydrogen flux to 0.1L / min to 3.0L / min, controlling the heating rate to 1°C / min to 15°C / min to heat to 150°C to 250°C, and keeping warm for 0.5h to 2h.

[0021] Optionally, the preparation method further includes a container cleaning step, which is performed before the substrate pretreatment step, and the container cleaning step includes: introducing an inert gas into the reaction container for multiple flushings, and pumping the pressure in the reaction container to 0.1Pa to 100Pa.

[0022] Optionally, the step of introducing raw gas comprises: introducing the silicon source into the reaction container by using a carrier gas, introducing a carbon source gas into the reaction container, and introducing hydrogen and the inert gas into the reaction container;

[0023] The steps of preparing the silicon carbide inner layer include: controlling the flux of the carrier gas to be 0.01L / min to 2L / min, controlling the flux of the hydrogen to be less than 4L / min, and controlling the flux of the inert gas to be 1L / min to 8L / min.

[0024] Optionally, the step of preparing the silicon carbide inner layer also includes: controlling the heating rate of the reaction container to 1°C / min-10°C / min to heat up to 900°C-1300°C, and keeping the temperature for 1h-10h to deposit the silicon carbide inner layer.

[0025] Optionally, the flux of the carrier gas is Q1, and the flux of the carbon source gas is Q2;

[0026] The step of preparing the silicon carbide transition layer includes: controlling Q1:Q2=(0:1):(0.1-10).

[0027] Optionally, the step of preparing the silicon carbide transition layer further includes: controlling the heating rate of the reaction container to 1°C / min-10°C / min to heat the temperature to 950°C-1200°C, and keeping the temperature for 1h-5h to deposit the silicon carbide transition layer.

[0028] Optionally, the step of preparing the silicon carbide transition layer further includes: controlling the ratio of the molar number of silicon in the silicon source to the molar number of carbon in the carbon source to be less than or equal to 2 / 3.

[0029] Optionally, after the step of preparing the silicon carbide layer, the following steps are performed: closing the channels of the silicon source, the carbon source gas and the hydrogen gas, controlling the flux of the inert gas to be 0 to 8 L / min, controlling the heating rate of the reaction container to be 1°C / min to 5°C / min, heating the temperature to 1200°C to 1600°C, and keeping the temperature for 1h to 3h.

[0030] Optionally, the step of preparing the tantalum carbide layer further includes: using a tantalum source conveying device to convey tantalum source powder to an evaporation device, and the evaporation device evaporates the tantalum source powder into tantalum source gas.

[0031] Optionally, the powder output rate of the tantalum source conveying device is 0.1 g / min to 15 g / min;

[0032] The temperature of the evaporation device is 100°C to 300°C.

[0033] Optionally, the deposition temperature of the tantalum carbide layer is 1900°C to 2200°C.

[0034] Optionally, the post-processing step comprises:

[0035] Closing the channels of the tantalum source, carbon source gas and hydrogen, and controlling the flux of the inert gas to 0-8 L / min;

[0036] Control the heating rate of the reaction container to be 1°C to 5°C / min.

[0037] 1800℃~2200℃, keep warm for 1h~2h;

[0038] Control the cooling rate of the reaction container to be 1°C to 5°C / min.

[0039] 1600℃~1800℃, keep warm for 1h~2h;

[0040] Control the cooling rate of the reaction container to be 5°C to 10°C / min.

[0041] 1200℃~1600℃, keep warm for 1h~2h;

[0042] Control the cooling rate of the reaction container to be 5°C to 20°C / min.

[0043] 800℃~1200℃, keep warm for 1h~2h;

[0044] Turn off power and allow furnace to cool.

[0045] Optionally, the carbonaceous substrate comprises at least one of graphite, carbon-carbon composite material, carbon felt, carbon fiber and diamond; and / or

[0046] The carbon source comprises at least one of methane, ethane, ethylene, acetylene, propane, propylene and butane; and / or

[0047] The silicon source comprises at least one of methyltrichlorosilane, trichlorosilane, silicon tetrachloride and dichlorosilane; and / or

[0048] The tantalum source includes at least one of tantalum methoxide, tantalum ethoxide, tantalum isopropoxide, tantalum butoxide and tantalum tetraethanolacetylacetonate; and / or

[0049] The inert gas is argon, and the carrier gas is argon or hydrogen.

[0050] A second aspect of the present application provides a semiconductor thermal field structure, the semiconductor thermal field structure comprising:

[0051] Carbonaceous substrate;

[0052] a silicon carbide layer, the silicon carbide layer being attached to the surface of the carbonaceous substrate;

[0053] A tantalum carbide layer is attached to a surface of the silicon carbide layer away from the carbonaceous substrate.

[0054] The semiconductor thermal field structure according to the present application has a technical effect similar to that of the preparation method described in the first aspect above.

[0055] Optionally, the silicon carbide layer comprises:

[0056] a silicon carbide inner layer, the silicon carbide inner layer being attached to the carbonaceous substrate;

[0057] A silicon carbide transition layer is attached to a surface of the silicon carbide inner layer away from the carbonaceous substrate, and the tantalum carbide layer is attached to a surface of the silicon carbide transition layer away from the silicon carbide transition layer.

[0058] Optionally, the morphology of the silicon carbide transition layer is rod-shaped, nanowire-shaped, cauliflower-shaped, hexagonal-shaped or pyramid-shaped.

[0059] Optionally, the ratio of the number of carbon atoms to the number of silicon atoms in the silicon carbide transition layer varies gradually along the thickness direction; and / or

[0060] The quantity ratio of carbon atoms to tantalum atoms in the tantalum carbide layer changes gradiently along the thickness direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0062] Figure 1 A simplified flow chart of a preparation method according to an embodiment of the present application is shown;

[0063] Figure 2 A detailed schematic flow chart of a preparation method according to an embodiment of the present application is shown;

[0064] Figure 3 A more detailed schematic flow chart of a preparation method according to an embodiment of the present application is shown; and

[0065] Figure 4 A schematic structural diagram of a semiconductor thermal field structure according to an embodiment of the present application is shown;

[0066] Figure 5A The state of the sample of Example 3 before calcination is shown;

[0067] Figure 5B The state of the sample of Example 3 after calcination is shown;

[0068] Fig. 6A The state of the sample of Comparative Example 1 before calcination is shown;

[0069] Figure 6B The state of the sample of Comparative Example 1 after calcination is shown. DETAILED DESCRIPTION

[0070] In order to make the purpose, technical solutions and advantages of the present application more obvious, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0071] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0072] It should be understood that the present application can be implemented in different forms and should not be interpreted as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0073] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0074] In order to thoroughly understand the present application, a detailed structure will be proposed in the following description to illustrate the technical solution proposed by the present application. The optional embodiments of the present application are described in detail as follows, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0075] The first aspect of the present application provides a preparation method for preparing a tantalum-containing composite coating on a carbonaceous substrate, referring to Figure 1 , the preparation method comprises the following steps:

[0076] A substrate preparation step, preparing a carbonaceous substrate and placing the carbonaceous substrate in a reaction container;

[0077] a step of preparing a silicon carbide layer, forming a silicon carbide layer on the surface of a carbonaceous substrate by chemical vapor deposition;

[0078] The step of preparing the tantalum carbide layer is to form the tantalum carbide layer on the surface of the silicon carbide layer by chemical vapor deposition.

[0079] According to the preparation method of the present application, by introducing a silicon carbide layer between the carbonaceous substrate and the tantalum carbide coating, the thermal expansion coefficient of silicon carbide is between that of the carbonaceous substrate and tantalum carbide, so as to reduce the thermal matching difference between the tantalum carbide coating and the carbonaceous substrate, thereby ensuring that the coating is resistant to high temperature and corrosion and is not easy to fall off.

[0080] More specifically, refer to Figure 2 The preparation method for preparing a tantalum-containing composite coating on the surface of a carbonaceous substrate in the present application can sequentially perform the following steps: a substrate preparation step, a container cleaning step, a substrate pretreatment step, a silicon carbide layer preparation step, a tantalum carbide layer preparation step, and a post-treatment step.

[0081] In the substrate preparation step, a carbonaceous substrate is prepared, processed into a suitable size and surface roughness, and the processed carbonaceous substrate is placed in a reaction vessel. The reaction vessel may be a vapor deposition furnace. The carbonaceous substrate may be selected from at least one of graphite, carbon-carbon composite material, carbon felt, carbon fiber and diamond.

[0082] In the container cleaning step, an inert gas is introduced into the reaction container for multiple flushing, and the pressure in the reaction container is pumped down to 0.1 Pa to 100 Pa. Argon gas can be selected as the inert gas.

[0083] In the substrate pretreatment step, the surface of the carbonaceous substrate is activated, wherein the activation treatment may be at least one of ultrasonic treatment, heat treatment, plasma treatment, acid treatment, alkali treatment and high temperature purification.

[0084] For example, the activation treatment may be: introducing hydrogen into the reaction container, performing temperature activation, controlling the hydrogen flux to be 0.1 L / min to 3.0 L / min, controlling the heating rate to be 1°C / min to 15°C / min to heat to 150°C, and keeping the temperature for 0.5h to 2h.

[0085] It is worth mentioning that when more than two activation treatments are used, a container cleaning step needs to be performed between two activation treatments. Preferably, the last activation treatment preferably adopts the above-mentioned hydrogen heating activation.

[0086] Pretreatment and activation do not damage the substrate, but can increase the surface roughness of the substrate, which is beneficial to increase the contact area between the coating and the substrate, and improve the surface activity, which is beneficial to the reaction of the coating components on the substrate surface, further improving the adhesion.

[0087] In the step of preparing the silicon carbide layer, refer to Figure 3 , the steps of introducing raw gas, preparing a silicon carbide inner layer and preparing a silicon carbide transition layer are performed in sequence, so that the silicon carbide layer includes a silicon carbide inner layer and a silicon carbide transition layer.

[0088] The step of introducing raw gas includes introducing a carbon source, a silicon source, hydrogen and an inert gas into the reaction container. The carbon source can be selected from at least one of methane, ethane, ethylene, acetylene, propane, propylene and butane. The silicon source can be selected from at least one of methyltrichlorosilane, trichlorosilane, silicon tetrachloride and dichlorosilane. More specifically, the silicon source is introduced into the reaction container by using a carrier gas, the carbon source gas is introduced into the reaction container, and hydrogen and an inert gas are introduced into the reaction container. The carrier gas is selected from argon and / or hydrogen.

[0089] In the step of preparing the silicon carbide inner layer, the silicon carbide inner layer is deposited on the surface of the carbonaceous substrate by chemical vapor deposition. Specifically, the flux of the carrier gas is controlled to be 0.01L / min to 2L / min, the flux of the carbon source gas is controlled to be less than 4L / min, and the flux of the hydrogen is controlled to be 1 to 8L / min. The heating rate of the reaction container is controlled to be 1°C / min to 10°C / min to 900°C to 1300°C, and the temperature is kept for 1h to 10h to deposit the silicon carbide inner layer.

[0090] Silicon carbide has a high melting point, which can reach 2700°C. After oxidation at high temperature, it can form molten SiO 2 , has fluidity, and can thus serve as a pore filler, hindering the diffusion of corrosive gases to a certain extent.

[0091] Then, the step of preparing a silicon carbide transition layer is performed, the ratio of the carbon source and the silicon source is changed, and the silicon carbide transition layer is deposited on the surface of the silicon carbide inner layer by chemical vapor deposition. Specifically, the flux of the carrier gas is Q1, and the flux of the carbon source gas is Q2. In the step of preparing the silicon carbide transition layer, it is necessary to control Q1:Q2=(0:1):(0.1~10). The ratio of the number of carbon atoms to silicon atoms in the silicon carbide transition layer thus formed changes gradiently along the thickness direction. Preferably, the deposition of the silicon carbide transition layer requires controlling the heating rate of the reaction vessel to be 1°C / min~10°C / min to heat to 950°C~1200°C, and keeping warm for 1h~5h. More preferably, it is necessary to control the ratio of the number of moles of carbon in the carbon source to the number of moles of silicon in the silicon source to be less than or equal to 2 / 3.

[0092] After the step of preparing the silicon carbide layer, perform the following steps: close the channels of the silicon source, carbon source gas and hydrogen, control the flux of the inert gas to 0-8 L / min, control the heating rate of the reaction container to 1°C / min-5°C / min, heat it to 1200°C-1600°C, and keep it warm for 1h-3h.

[0093] Then, a step of preparing a tantalum carbide layer is performed. Specifically, the silicon source is turned off, a tantalum source is introduced into the reaction container, and a tantalum carbide layer is deposited on the surface of the silicon carbide transition layer. The tantalum source includes at least one of tantalum methoxide, tantalum ethoxide, tantalum isopropoxide, tantalum butoxide, and tantalum tetraethanol acetylacetonate.

[0094] The tantalum source conveying device is used to convey the tantalum source powder to the evaporation device, and the powder output rate of the tantalum source conveying device is 0.1g / min to 15g / min. The evaporation device evaporates the tantalum source powder into tantalum source gas, and the temperature of the evaporation device is 100℃ to 300℃. Then, the reaction container is controlled to be 1900℃ to 2200℃ to deposit the tantalum carbide layer.

[0095] After the step of preparing the tantalum carbide layer is completed, a post-processing step is performed, specifically, the carbon source, the tantalum source and the hydrogen are turned off, and an inert gas is continuously introduced into the reaction container to perform a gradient temperature reduction.

[0096] More specifically, in the post-processing step, first close the channels of the tantalum source, carbon source gas and hydrogen, and control the flux of the inert gas to 0-8 L / min. Then control the heating rate of the reaction vessel to be 1°C / min-5°C / min and heat it to 1800°C-2200°C, and keep it warm for 1h-2h. Then control the cooling rate of the reaction vessel to be 1°C / min-5°C / min and cool it to 1600°C-1800°C, and keep it warm for 1h-2h. Then control the cooling rate of the reaction vessel to be 5°C / min-10°C / min and cool it to

[0097] 1200℃~1600℃, keep warm for 1h~2h. Then control the cooling rate of the reaction vessel to 5℃ / min~20℃ / min and cool to 800℃~1200℃, keep warm for 1h~2h. Finally, turn off the power and cool with the furnace. This slow gradient cooling form helps to eliminate some stress.

[0098] In summary, a multilayer structure as shown in the figure can be formed, that is, a silicon carbide inner layer is attached to the surface of the carbonaceous substrate, a silicon carbide transition layer is attached to the surface of the silicon carbide inner layer, and a tantalum carbide layer is attached to the surface of the silicon carbide transition layer.

[0099] Example 1

[0100] The density is 1.78 g / cm 3 The graphite was processed into a graphite block with a size of 50×50×10 mm and a roughness Ra of 2.0 μm. The graphite block was ultrasonically cleaned three times with ethanol and deionized water in turn, and then dried in an oven at 100°C for 2 hours.

[0101] The dried graphite was placed in a purification furnace and purified to less than 20 ppm. The purified graphite was placed in a plasma cleaning machine and evacuated to less than 10 Pa. Then oxygen was introduced at a flux of 15 sccm, and the plasma excitation power was set to 200 W and treated for 2 minutes.

[0102] The plasma-treated graphite was placed in the chamber of the CVD furnace, and the vacuum pump was turned on to evacuate to 80 Pa. Then, argon gas was introduced until the pressure reached 30,000 Pa. The argon gas channel was closed and then evacuated to 80 Pa. This process was repeated three times.

[0103] Hydrogen was introduced into the cleaned vacuum chamber at a flux of 1 L / min, and the chamber was heated to 200°C at a rate of 10°C / min and kept at that temperature for 1 hour, and then the hydrogen channel was closed. Then the argon channel was opened and the flux was controlled to be 3 L / min.

[0104] First deposition (silicon carbide inner layer): control the chamber temperature to 900°C at a rate of 10°C / min, open the channels of methane and hydrogen, control the flux to 1L / min, and keep warm for 2h.

[0105] Second deposition (silicon carbide transition layer): Control the chamber temperature to 1050°C at a rate of 5°C / min, maintain the methane flux at 1L / min, open the hydrogen carrier gas into the MTS tank, the flux is 0.5L / min, and keep warm for 2h.

[0106] Close the methane channel, control the chamber temperature to 1150°C at a rate of 5°C / min, adjust the hydrogen carrier gas flux to 1L / min, and keep warm for 4h.

[0107] The channels of hydrogen carrier gas and hydrogen were closed, and the temperature of the chamber was controlled to rise to 1700°C at a rate of 5°C / min, kept at that temperature for 0.5h, and then raised to 2100°C at a rate of 3°C / min.

[0108] The third deposition (tantalum carbide layer): open the tantalum source evaporator, raise the temperature to 200 ° C, TaCl 5 The powder feeder discharges powder to the tantalum source evaporator at a rate of 5 g / min. The fluxes of argon, methane and hydrogen are set to 2 L / min, 2 L / min and 1 L / min respectively, and the temperature is kept at 2100°C for 6 hours.

[0109] Turn off the tantalum source powder feeder, evaporator, methane, and hydrogen, adjust the argon flux to 4L / min, cool down to 1800℃ at a rate of 2℃ / min and keep it for 1h, cool down to 1600℃ at a rate of 5℃ / min and keep it for 1h, cool down to 1200℃ at a rate of 10℃ / min and keep it for 0.5h, cool down to 800℃ at a rate of 20℃ / min and keep it for 0.5h. Then turn off the power, cool down to 80℃ with the furnace and take out the sample.

[0110] Example 2

[0111] The density is 1.83 g / cm 3 The isostatic graphite was processed into a graphite block with a size of 100×100×20 mm and a roughness Ra of 1.6 μm. It was placed in nitric acid and refluxed in a water bath at 80°C for 1 hour, taken out and washed with deionized water, and then placed in a 100°C oven to dry for 2 hours.

[0112] The dried graphite was placed in a purification furnace and purified to less than 10 ppm. The purified graphite was placed in the chamber of a CVD furnace, the vacuum pump was turned on and pumped to 20 Pa, then argon gas was introduced to a pressure of 50,000 Pa, the argon gas was turned off and then pumped to 20 Pa, and this was repeated three times.

[0113] Hydrogen was introduced into the cleaned vacuum chamber at a flux of 1.5 L / min, and the chamber was heated to 240°C at a rate of 10°C / min and kept warm for 1 h. The hydrogen was then turned off, and the argon channel was opened and the flux was controlled to 2 L / min.

[0114] First deposition (silicon carbide inner layer): Control the chamber temperature to 1200℃ at a rate of 10℃ / min, turn on SiHCl 3 The carrier gas, acetylene and hydrogen, had fluxes controlled at 0.1 L / min, 0.6 L / min and 2 L / min, respectively, and was kept warm for 1 h.

[0115] Second deposition (SiC transition layer): Adjustment of SiHCl 3The carrier gas, acetylene and hydrogen, fluxes were controlled at 0.1 L / min, 0.3 L / min and 2 L / min respectively, and the temperature was kept for 2 h.

[0116] Adjustment of SiHCl 3 The carrier gas, acetylene, hydrogen and argon, were controlled at fluxes of 0.2 L / min, 0.2 L / min, 2 L / min and 3 L / min, respectively, and kept warm for 2 h.

[0117] Shut down SiHCl 3 The carrier gas, acetylene and hydrogen, controlled the chamber temperature to rise to 1650°C at 8°C / min and kept at this temperature for 1h.

[0118] The third deposition (tantalum carbide layer): control the chamber temperature to 2200°C at 4°C / min, open the argon carrier gas to pass into the ethanol tantalum raw material tank, set the carrier gas flux to 0.1L / min, and set the acetylene and hydrogen fluxes to 0.4L / min and 4L / min respectively, and keep it at 2200°C for 4h.

[0119] Adjust the fluxes of argon carrier gas, acetylene, and hydrogen to 0.5 L / min, 0.5 L / min, and 3.5 L / min, respectively, and keep warm for 10 hours.

[0120] Turn off the tantalum source carrier gas, acetylene and hydrogen, adjust the argon flux to 5L / min, control the chamber to cool down to 1800℃ at a rate of 4℃ / min and keep it for 1h, then cool down to 1600℃ at a rate of 4℃ / min and keep it for 1h, then cool down to 1400℃ at a rate of 8℃ / min and keep it for 1h, then cool down to 800℃ at a rate of 15℃ / min and keep it for 1h. Then turn off the power, cool down to 80℃ with the furnace and take out the sample.

[0121] Example 3

[0122] Isostatically pressed graphite was processed into a graphite piece with a roughness Ra of 2.4 μm. The graphite piece was ultrasonically cleaned three times with acetone and deionized water in sequence, and then placed in a reaction chamber of a chemical vapor deposition furnace after drying.

[0123] The reaction chamber was evacuated to 50 Pa and then heated to 300 °C at a rate of 10 °C / min. H was introduced at a flux of 1 L / min. 2 , keep warm for 20 minutes.

[0124] First deposition (silicon carbide inner layer): heat up to 900°C at a rate of 5°C / min, with a flux of methane 2L / min, hydrogen 1L / min, and argon 2L / min, and keep the reaction warm for 120min. After the reaction, turn off the methane and hydrogen.

[0125] Second deposition (silicon carbide transition layer): heat up to 1200°C at a heating rate of 3°C / min, with methyltrichlorosilane carrier gas of 1.5L / min, hydrogen gas of 2L / min, and argon gas of 5L / min, react for 8h, and then turn off the methyltrichlorosilane carrier gas and hydrogen.

[0126] The temperature was raised to 2150°C at a rate of 2°C / min. When the reaction chamber was raised to 2000°C, the temperature of the tantalum source evaporation tank was raised to 200°C at a rate of 5°C / min.

[0127] Third deposition (tantalum carbide layer): Controlled TaCl 5 The powder feeder discharges powder to the tantalum source evaporator at a rate of 8 g / min. The fluxes of methane, hydrogen and argon are set to 2.5 L / min, 5 L / min and 8 L / min respectively, and the temperature is kept at 2150°C for 7 hours.

[0128] Turn off the tantalum source, methane and hydrogen, cool down to 1850℃ at a rate of 3℃ / min and keep warm for 30min, then cool down to 1550℃ at a rate of 3℃ / min and keep warm for 30min, then cool down to 1200℃ at a rate of 5℃ / min and keep warm for 30min, then turn off the power and cool to 80℃ with the furnace to take out the sample.

[0129] Comparative Example 1

[0130] The steps are basically the same as those in Example 3, except that methane and hydrogen are not introduced in the second deposition, and methyltrichlorosilane and hydrogen are not introduced in the third deposition, thereby obtaining a sample with a tantalum carbide coating deposited directly on a graphite substrate.

[0131] The samples made in Example 3 were compared with the samples made in Comparative Example 1: the two samples were calcined at 1700° C. for 20 h in a high-temperature furnace with an Ar atmosphere, and the coating changes were compared.

[0132] in, Figure 5A and Figure 5B The states of the sample of comparative example 1 before and after calcination are shown respectively. Fig. 6A and Figure 6B The states of the sample of Example 3 before and after calcination are shown respectively.

[0133] Depend on FIG. 5A to FIG. 6B It can be seen that the sample of comparative example 1 has a part of the deposited TaC coating falling off after high-temperature calcination, while the sample of embodiment 3 has almost no change after calcination under the same conditions due to the presence of the silicon carbide transition layer, indicating that the coating has good bonding strength.

[0134] The second aspect of the present application provides a semiconductor thermal field structure, which is manufactured by the preparation method of the first aspect, and the semiconductor thermal field structure includes a carbonaceous substrate, a silicon carbide layer and a tantalum carbide layer. The silicon carbide layer is attached to the surface of the carbonaceous substrate. The tantalum carbide layer is attached to the surface of the silicon carbide layer. The semiconductor thermal field structure according to the present application has a technical effect similar to that of the preparation method of the first aspect.

[0135] As a preferred embodiment, the silicon carbide layer includes a silicon carbide inner layer and a silicon carbide transition layer. The silicon carbide inner layer is attached to the carbonaceous substrate. The silicon carbide transition layer is attached to the silicon carbide inner layer, and the tantalum carbide layer is attached to the silicon carbide transition layer.

[0136] By utilizing the flexible and adjustable characteristics of chemical vapor deposition, the ratio of carbon atoms to silicon atoms in the silicon carbide transition layer and the ratio of carbon atoms to tantalum atoms in the tantalum carbide layer are changed in a gradient along the thickness direction through the dynamic and continuous delivery of raw materials. This is conducive to reducing the thermal expansion difference between the graphite phase and the silicon carbide phase, and between the silicon carbide phase and the tantalum carbide phase, obtaining a tightly bonded composite coating and improving thermal shock resistance.

[0137] As an implementation form, the morphology of the silicon carbide transition layer is rod-shaped, nanowire-shaped, cauliflower-shaped, hexagonal prism-shaped or pyramid-shaped. Preferably, when the silicon carbide in the silicon carbide transition layer is nanowire-shaped carbon, the crack can be deflected and energy can be consumed. At the same time, the crack propagation resistance can be increased due to the pull-out and bridging of the nanowires during cracking.

[0138] The processes and steps described in all the above preferred embodiments are only examples. Unless adverse effects occur, various processing operations can be performed in a sequence different from the sequence of the above processes. The sequence of steps in the above processes can also be increased, merged or deleted according to actual needs.

[0139] It should be noted that the above embodiments illustrate rather than limit the present application, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets should not be constructed as a limitation to the claims. The present application may be implemented by means of hardware including several different elements and by means of a suitably programmed computer. In a unit claim that lists several devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names.

[0140] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present application. The terms used herein are only for describing specific implementation purposes and are not intended to limit the present application. The features described herein in one embodiment may be applied to another embodiment individually or in combination with other features, unless the feature is not applicable or otherwise specified in the other embodiment.

Claims

1. A method for preparing a semiconductor thermal field structure, characterized in that: The preparation method comprises the following steps: providing a carbonaceous substrate; forming a silicon carbide layer on the surface of the carbonaceous substrate by chemical vapor deposition; A tantalum carbide layer is formed on a surface of the silicon carbide layer away from the carbonaceous substrate by chemical vapor deposition.

2. The preparation method according to claim 1, characterized in that: The silicon carbide layer includes a silicon carbide inner layer and a silicon carbide transition layer, and the step of preparing the silicon carbide layer further includes: A raw material gas introduction step, wherein a carbon source, a silicon source, hydrogen and an inert gas are introduced into the reaction container; a step of preparing a silicon carbide inner layer, depositing the silicon carbide inner layer on the surface of the carbonaceous substrate; The step of preparing the silicon carbide transition layer comprises changing the ratio of the carbon source and the silicon source, and depositing the silicon carbide transition layer on the surface of the silicon carbide inner layer.

3. The preparation method according to claim 2, characterized in that: The step of preparing the tantalum carbide layer also includes: closing the silicon source, introducing a tantalum source into the reaction container, and depositing the tantalum carbide layer on the surface of the silicon carbide transition layer.

4. The preparation method according to claim 3, characterized in that: The preparation method further comprises: A post-processing step is performed after the step of preparing the tantalum carbide layer, and the post-processing step includes: shutting off the carbon source, the tantalum source and the hydrogen, and continuing to introduce the inert gas into the reaction container for gradient cooling.

5. The preparation method according to claim 1, characterized in that: The preparation method further comprises a substrate pretreatment step, which is performed before the step of preparing the silicon carbide layer. The substrate pretreatment step comprises: performing activation treatment on the surface of the carbonaceous substrate.

6. The preparation method according to claim 5, characterized in that: The activation treatment includes at least one of ultrasonic treatment, heat treatment, plasma treatment, acid treatment, alkali treatment and high temperature purification.

7. The preparation method according to claim 5, characterized in that: The activation treatment includes: introducing hydrogen into the reaction container, performing temperature activation, controlling the hydrogen flux to be 0.1L / min to 3.0L / min, controlling the heating rate to be 1°C / min to 15°C / min to heat to 150°C to 250°C, and keeping the temperature for 0.5h to 2h.

8. The preparation method according to claim 5, characterized in that: The preparation method further includes a container cleaning step, which is performed before the substrate pretreatment step. The container cleaning step includes: introducing an inert gas into the reaction container for multiple flushings, and pumping the pressure in the reaction container to 0.1Pa to 100Pa.

9. The preparation method according to claim 3, characterized in that: The step of introducing raw gas comprises: using a carrier gas to carry the silicon source into the reaction container, introducing a carbon source gas into the reaction container, and introducing hydrogen and the inert gas into the reaction container; The steps of preparing the silicon carbide inner layer include: controlling the flux of the carrier gas to be 0.01L / min to 2L / min, controlling the flux of the hydrogen to be less than 4L / min, and controlling the flux of the inert gas to be 1L / min to 8L / min.

10. The preparation method according to claim 9, characterized in that: The step of preparing the silicon carbide inner layer also includes: controlling the heating rate of the reaction container to be 1°C to 10°C / min to heat up to 900°C to 1300°C, and keeping the temperature for 1h to 10h to deposit the silicon carbide inner layer.

11. The preparation method according to claim 9, characterized in that: The flux of the carrier gas is Q1, and the flux of the hydrogen is Q2; The step of preparing the silicon carbide transition layer includes: controlling Q1:Q2=(0:1):(0.1-10).

12. The preparation method according to claim 11, characterized in that: The step of preparing the silicon carbide transition layer also includes: controlling the heating rate of the reaction container to be 1°C to 10°C / min to heat up to 950°C to 1200°C, and keeping the temperature for 1h to 5h to deposit the silicon carbide transition layer.

13. The preparation method according to claim 11, characterized in that: The step of preparing the silicon carbide transition layer also includes: controlling the ratio of the molar number of silicon in the silicon source to the molar number of carbon in the carbon source to be less than or equal to 2 / 3.

14. The preparation method according to claim 11, characterized in that: After the step of preparing the silicon carbide layer, the following steps are performed: closing the channels of the silicon source, the carbon source gas and the hydrogen gas, controlling the flux of the inert gas to be 0 to 8 L / min, controlling the heating rate of the reaction container to be 1°C / min to 5°C / min, heating to 1200°C to 1600°C, and keeping the temperature for 1h to 3h.

15. The preparation method according to claim 3, characterized in that: The step of preparing the tantalum carbide layer also includes: using a tantalum source conveying device to convey tantalum source powder to an evaporating device, and the evaporating device evaporates the tantalum source powder into tantalum source gas.

16. The preparation method according to claim 15, characterized in that: The powder output rate of the tantalum source conveying device is 0.1 g / min to 15 g / min; The temperature of the evaporation device is 100°C to 300°C.

17. The preparation method according to claim 15, characterized in that: The deposition temperature of the tantalum carbide layer is 1900°C to 2200°C.

18. The preparation method according to claim 4, characterized in that: The post-processing steps include: Closing the channels of the tantalum source, carbon source gas and hydrogen, and controlling the flux of the inert gas to be 0 to 8 L / min; Control the heating rate of the reaction container to be 1°C to 5°C / min, raise the temperature to 1800°C to 2200°C, and keep the temperature for 1h to 2h; Control the cooling rate of the reaction container to be 1°C to 5°C / min, cool down to 1600°C to 1800°C, and keep warm for 1h to 2h; Control the cooling rate of the reaction container to be 5°C to 10°C / min, cool to 1200°C to 1600°C, and keep warm for 1h to 2h; Control the cooling rate of the reaction container to be 5°C to 20°C / min, cool to 800°C to 1200°C, and keep warm for 1h to 2h; Turn off power and allow furnace to cool.

19. The preparation method according to claim 9, characterized in that: The carbonaceous substrate comprises at least one of graphite, carbon-carbon composite material, carbon felt, carbon fiber and diamond; and / or The carbon source comprises at least one of methane, ethane, ethylene, acetylene, propane, propylene and butane; and / or The silicon source comprises at least one of methyltrichlorosilane, trichlorosilane, silicon tetrachloride and dichlorosilane; and / or The tantalum source includes at least one of tantalum methoxide, tantalum ethoxide, tantalum isopropoxide, tantalum butoxide and tantalum tetraethanolacetylacetonate; and / or The inert gas is argon, and the carrier gas is argon or hydrogen.

20. A semiconductor thermal field structure, characterized in that: The semiconductor thermal field structure comprises: Carbonaceous substrate; a silicon carbide layer, the silicon carbide layer being attached to a surface of the carbonaceous substrate; A tantalum carbide layer is attached to a surface of the silicon carbide layer away from the carbonaceous substrate.

21. The semiconductor thermal field structure according to claim 20, characterized in that: The silicon carbide layer comprises: a silicon carbide inner layer, the silicon carbide inner layer being attached to the carbonaceous substrate; A silicon carbide transition layer is attached to a surface of the silicon carbide inner layer away from the carbonaceous substrate, and the tantalum carbide layer is attached to a surface of the silicon carbide transition layer away from the silicon carbide transition layer.

22. The semiconductor thermal field structure according to claim 21, characterized in that: The morphology of the silicon carbide transition layer is rod-shaped, nanowire-shaped, cauliflower-shaped, hexagonal-shaped or pyramid-shaped.

23. The semiconductor thermal field structure according to claim 21, characterized in that: The ratio of the number of carbon atoms to silicon atoms in the silicon carbide transition layer varies gradually along the thickness direction; and / or The quantity ratio of carbon atoms to tantalum atoms in the tantalum carbide layer changes gradiently along the thickness direction.

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